I am helping a friend build a new flea circus. He decided to utilize small solenoids to activate several of the circus events. I put together a short description of how the solenoids were modified to allow attaching the required mechanisms for the desired movements done by the "fleas". I thought this might be of use to others creating such goodies. If interested, it may be seen here: http://jamesriser.com/Solenoid.pdf

Several folks have asked how we are getting the fleas to activate the various events in the circus. The flea power is being harnessed by Arduino with an emergency pause/resume button. This will allow the presenter to concentrate on the presentation and not have to constantly reach behind the circus to flick the fleas into action.